Transmitter tube



July 2s, 1936. M. WETH ET AL 4 2,049,238

I TRANSMITTER TUBE Filed Oct. 18, 1932 nnnnnnn null lllH INVENTORS MAX ETH WILHELMTRAUB ATT oNEY Patented July 28, 1936 UNITED STATES PATENT OFFICE TRANSMITTER TUBE Application October 18, 1932, Serial No. 638,324 In Germany October 19, 1931 3 Claims. (01. 25 27.5)

The load capacity of transmitter and rectifier tubes is limited, inter alia, and most particularly, by the heating of the anodes or plates. The latter are mostly made of copper in the case of water-cooled tubes, for copper is especially favorable for reasons of its high heat conducting powers. On the other hand, however, copper has the. drawback that it readily evaporates and disintegrates (spatters or vaporizes), most par- 0 ticularly in case of electron bombardment. Especially when the anode is not uniformly impacted by electrons, indeed, when local portions thereof are struck particularly strongly by electrons will the risk of local fusion of the copper be caused to arise. Indeed, there have been instances where tubes have been destroyed or rendered unserviceable for the reason that at one or more places of the anode, punctures or holes have been produced as a result of the impinging of concentrated electron pencils.

Now, the present invention is concerned with a special form of construction of the anodes of water-cooled tubes or rectifiers whereby the load capacity thereof is considerably raised, while such shortcomings as have hereinbefore been cited will be avoided.

It has been discovered that the anode is capable of far larger loads when made from a difficultly fusible substance which is embedded in 30 another material of high thermal conduction powers such as copper, in such a way that an intimate thermic contact is assured. Difiicultly melting materials such as tungsten, tantalum, molybdenum, etc., quite apart from their ex- 35 cellent high-vacuum properties, as is well known,

possess this further advantage that they are diflicultly vaporizable so that they are able to withstand the bombardment of electrons without being impaired thereby. As a result of embedding such dimcultly vaporizable substances in a metal such as copper, it is feasible to readily abduct (dissipate) large volumes of heat. The intimate contact between the difiicultly fusible constituent and the one capable of high heat conduction may 45 be insured by soldering (welding together) or still better by that the cylinder consisting of difiicultly fusible substance is cast or poured into a sheath or casing possessing high heat conducting properties, this being accomplished preferably in vacuo.

Another embodiment of the invention consists in that a copper cylinder or the like is interiorly coated with the powder of a difiicultly meltable metal by that, for instance, a paste of pulverulent tungsten, zirconium, titanium, or the like, is applied in the interior of the cylinder and, optionally, is caused to adhere by concretion or sintering. What is essential, at any rate, is that the union between the two parts should be so that an intimate thermal contact will be assured.

In the drawing a tube is shown equipped with an anode or plate as here disclosed. Referring to the same, I denotes the anode or plate cylinder or body of substantially cylindrical shape made of the difi'icultly fusible substance, 2 is the body consisting of the body possessing high heat conductivity. The filament 3 and the grid 4 are accommodated within the tube in the customary manner.

We claim:

1. A liquid cooled electron discharge device comprising an evacuated vessel, an anode which constitutes a portion of said vessel, and a cathode disposed therein, said anode being formed of two layers of different metals in intimate thermal contact with each other, the inner layer made of tungsten cooperating with the cathode to collect the electrons emitted therefrom and the outer layer made of copper adapted to cooperate with the cooling liquid.

2. A liquid cooled electron discharge device comprising an evacuated vessel, an anode which constitutes a portion of said vessel, and a cathode disposed therein, said anode being in the form of a cylindrical copper shell to the inner surface of which there is applied a coating of paste composed of powdered tungsten.

3. A vacuum tube device comprising a glass portion, a gas-tight copper shell portion sealed thereto and acting as an exterior electrode, a tungsten sleeve welded to the inner surface of the copper shell, and an interior electrode cooperating with said tungsten sleeve.

MAX WETH. WILI-IELM TRAUB. 

